Anatomy - Internal Heart and Posterior Mediastinum

Question 1

What are the 2 main branches the LCA gives rise to?

Answer 1

1. Circumflex artery 2. Anterior interventricular artery (left anterior descending artery)

Question 2

What does left circumflex artery then give rise to?

Answer 2

Marginal branch

Question 3

What does the left anterior interventricular artery give rise to?

Answer 3

Diagonal branch

Question 4

What does left anterior interventricular artery supply?

Answer 4

Predominance of left ventricle

Question 5

What is the slight indentation on the intertartrial septum?

Answer 5

Fossa ovalis

Question 6

What is the fossa ovalis?

Answer 6

Remnant of vascular shunt bypassing lungs (foramen ovale in foetal)

Question 7

What is the rough part of the atrial wall?

Answer 7

Pectinate muscles

Question 8

What separates the smooth from the rough parts of the atrial wall?

Answer 8

Crista terminalis (muscular ridge)

Question 9

Why is the left atrium smoother than the right?

Answer 9

Pulmonary veins have been encompassed into the left atrial wall

Question 10

What attach the edge of the cusps and anchor valves to ventricular wall?

Answer 10

Chordae tendinae

Question 11

What are chordae tendinae held in place by?

Answer 11

Papillary muscles

Question 12

What are papillary muscles elevations from?

Answer 12

Trabeculae carnae

Question 13

What is the trabeculae carnae?

Answer 13

Roughened musculature of ventricles

Question 14

Are trabeculae carnae more prevalent in left or right ventricle?

Answer 14

Left

Question 15

Function of papillary muscles?

Answer 15

Contract to prevent tricuspid valve from prolapsing back into right atrium during diastole

Question 16

What is the ‘moderator band’?

Answer 16

Just before impulse from SA node causes ventricular systole, there is some nervous tissue/Purkinje fibres that project through moderator band to papillary muscles a millisecond before ventricular systole. Enables papillary muscles to contract and pull on chordae tendinae to keep tricuspid valve taught during ventricular systole (stops prolapsing)

Question 17

What does the trachea bifurcate into?

Answer 17

Right and left primary bronchi

Question 18

What structure causes constriction of oesophagus?

Answer 18

Left bronchus crosses muscular tube (oesophagus) behind it, causing constriction

Question 19

What is the ‘carina’?

Answer 19

A ridge of cartilage in the trachea that occurs between the division of the two main bronchi

Question 20

What drains the thoracic cage?

Answer 20

Azygos vein which eventually empties into SVC

Question 21

What drains all the lymph from the lower half of the body?

Answer 21

Thoracic duct

Question 22

What is function of thoracic duct?

Answer 22

Drains lymph from lower half of body

Question 23

Where does thoracic duct empty into?

Answer 23

Area where subclavian and jugular vein merge to make brachiocephalic vein

Question 24

What can damage to thoracic duct lead to?

Answer 24

Lymph within thoracic cavity

Question 25

Where does the trachea bifurcate?

Answer 25

At the carina

Question 26

What is a chylothorax?

Answer 26

Accumulation of lymph fluid in the thoracic cavity due to damage to the thoracic duct

Question 27

Papillary vs pectinate muscles?

Answer 27

Pectinate –> elevations from atria wall (form rough part of atria)

Papillary muscles –> elevations from trabeculae carnae, attach to chordae tendinae and then to cusps of valves

Question 28

How does the trachea deviate?

Answer 28

Deviates slightly towards the right as it descends –> left primary bronchus causes obstruction of oesophagus